The present invention relates to an image scanning system, and particularly to a system that scans a strip of photographic film or mounted slide containing an image or images, and creates digital representations of the images.
There has been a continuing need for high speed and inexpensive film scanners that scan photographic film strips and slide mounts and generate high quality digital images. Pakon, Inc., the assignee of the present invention, has developed film scanners which are described in U.S. Pat. No. 5,872,591, and U.S. patent application Ser. No. 09/149,612, filed on Sep. 8, 1998, which are hereby incorporated by reference.
Due to the ever increasing processing power of personal computers, it would be desirable for a film scanning system to take advantage of this processing power for processing and manipulation of image data. In the past, there have been bandwidth limitations on the interface between film scanners and personal computers which have limited the ability of scanners to pass large bandwidth data to computers. In addition, computers did not have adequate processing power to quickly and efficiently process the data once received. Prior scanning systems have attempted to deal with this problem by reducing the color depth of the image data prior to transferring it to the computer for processing. However, a reduction in the color depth results in a reduction in image quality. It would be desirable for a film scanning system to make use of a high speed computer with a high-speed interface that allows large bandwidth image data to be transferred from the scanner to the personal computer without the need for reducing the color depth.
It would also be desirable for a scanning system to be scalable to take advantage of increasing computer speeds. By using the computer to perform most of the data processing operations, rather than the scanner itself, the speed of the scanning process can easily be scaled up by using a higher speed computer. Thus, increased performance may be obtained without having to change scanner hardware or software.
A further improvement that would be desirable in a scanning system would be for the system to use a distributed design that utilizes several microprocessor-based subsystems connected by a single ribbon cable, rather than a more central design with a single processor and numerous cables running throughout the scanner. A distributed design reduces the necessary cabling and the cost of the system.
In addition to speed limitations, another disadvantage of prior art scanners is that they are typically limited to scanning only one type of film, or they require attachments such as different film gates to scan different types of film. With the variety of films that are available today, it would be useful to have a single scanner that can scan different types of film and slides without changing the hardware configuration.